The present invention relates to an automatic rhythm generator and in particular to an electronic rhythm generator adapted for incorporation into an electronic organ as an integral part thereof.
Electronic rhythm generators are well known and generally provide a relatively full complement of percussion sounds, such as brush, cymbal, snare drum, wood block, etc., which are selectively combined in a predetermined sequence and at a rate and spacing which is determined by the particular rhythm selected by the player. For example, a given rhythm sequence may include snare drum, brush, and cymbal percussion sounds which are arranged in a rhythmically pleasing fashion. Generally, the selected rhythm sequence is cycled repetitively every so many measures, which normally comprise sixteen beats each, without the necessity for any intervention by the player.
In order to prevent the rhythm sequence from becoming monotonous, some organs have been provided with break generators, which produce a one or two measure rhythm break sequence which, although rhythmically compatible with the normal rhythm pattern, are sufficiently different to impart a pleasing diversion from the normal rhythm pattern. Because most rhythm patterns are initiated immediately upon depression of the controlling switch or pedal, and terminate when the switch or pedal is released, there is a certain abruptness to the initiation and determination of the rhythm sequence, which causes an unnatural and artificial effect. A rhythm break sequence is advantageous at the beginning and especially at the end of a musical composition to provide a smooth transition into and out of the composition.
Early rhythm units have typically comprised actual rhythm devices, such as drums, cymbals, etc., which were played directly from a keyboard. Obviously, this is unsatisfactory, both from the standpoint of cost and the necessity for the rhythm unit to be played manually by the performer. Later rhythm units were automatic and incorporated electronic sound generators, but the circuitry and mechanical devices for scanning and other control functions were bulky, expensive and unreliable and noisy. With the advent of modern electronics and solid state technology, the circuitry could be greatly simplified and reduced in size and cost, but a large number of components were still necessary thereby creating problems related to complex switching and parts.
MOS technology has enabled the storage capacity and control capability of electronic automatic rhythm generators to be greatly expanded due to the fact that the rhythm patterns can be stored in a read only memory. When using a read only memory for this purpose, however, a great number of external parts are required, such as complex switching, and, due to cost factors, special control circuitry for facilitating operation of the rhythm generator is often not implemented. For example, in one prior art rhythm break generation system, the rhythm break will not operate when a particular rhythmical meter, such as 3/4 meter, is selected, but the rhythm unit will shut down. This detracts from the automatic character of the rhythm unit and makes it difficult for inexperienced players to use.
Since most present day rhythm units are integrated with the existing organ circuitry, it becomes important for the unit to be adapted for use with a number of organ models, ranging from the single keyboard spinets to the larger consoles without extensive modification. Furthermore, since much of the automatic play features of an electronic organ, such as automatic bass patterns and the like, are controlled and synchronized by the rhythm generator, it may be necessary for some of the rhythm generator channel outputs to remain in operation, during a rhythm break. Selective control of the instrument output channels is, therefore, a desirable feature.